Coffee, tea and beverages made from untreated R/O water can be bitter, sour, flat and metallic tasting. Total dissolved solids (TDS) means the total amount of solids that can be recovered in dry form when water is evaporated off of the functional water. R/O water is purified H2O having little or no hardiness ions.
Tap water is a complex solution of chemicals, organics and minerals, and has pH and alkalinity characteristics. Each of these has an effect on the quality of coffee and beverages.
Total Dissolved Solids: During the brewing process solids are extracted from the coffee grounds and without consistent TDS levels the quality of coffee and espresso can range greatly from strong and bitter to weak and underdeveloped. Without controlling the TDS level the consistency of the beverage will vary. Low TDS (<50 ppm) can result in a bitter or tart tasting coffee and espresso. High TDS (>500 ppm) could mean that sodium, calcium, chloride and magnesium are detectable in the final product. Also, high TDS saturated water will not extract at full strength as there is no space left to add the finest of the coffee.
Total Hardness: Hardness ions, such as calcium and magnesium, bind with the extracted coffee bean organics from the brewing process to give the correct flavor to the coffee and espresso beverages. Minerals also help to reduce the acidity of water. Without the proper amount of hardness mineral your coffee will have a high level of astringency or be very bitter.
pH: Water below 7.0 is acidic and corrosive, water above 7.0 is basic and caustic. Natural low pH indicates a lack of mineral in the water, so water will taste flat or bitter (it's like drinking distilled water, which has a pH of about 5.5). As pH increases (>7) the result is an astringent taste. Higher pH also usually indicates a higher alkalinity and possibility of limescale. Due to the fact that a person with sensitive taste can notice a pH shift of as little as 0.1, controlling pH is vital to consistency and taste. The ideal is a pH of around 7.0 to 8.0.
Alkalinity: High alkalinity is a catalyst for scale development in the brewing equipment.
Total Chlorides: Elevated levels of total chlorides are most commonly associated with salt. In normal levels, chlorides will result in a sweet taste to brewed beverages, but at elevated levels can cause sourness. Chlorides are also especially corrosive on stainless steel, quickly eating away at exposed components.
Chlorine: Chlorine can alter the aroma and taste of coffee/espresso by oxidizing the aromatics and oils, reducing the pH balance and imparting chemical/medicinal odors and tastes. Chlorine readily bonds with organics to create compounds that can impart an “earthy or moldy” tone to coffee. In addition, chlorine causes corrosion on metals and can cause brittle o-rings and gaskets (quality commercial espresso machines use Teflon gaskets, especially at the boiler, which helps to reduce chemical-induced problems).
Particulates (dirt, sediment, ferric metals, organic material): These cause plugging of orifices and abrasion on surfaces.
Related prior art includes Pub. No. U.S. 2004/0241299 (2004) to Zhang which discloses the ideal water for making tea. Pub. No. U.S. 2004/0022898 (2004) to Zucker discloses a method to use sea water and adjust sodium, manganese, potassium, and calcium to produce ideal beverage water. An R/O system is used. U.S. Pat. No. 5,597,487 (1997) to Vogel et al. discloses a R/O water purifier for a store or kiosk that injects calcium chloride, potassium chloride, and/or magnesium chloride to create a TDS of up to 100 ppm for drinking water. These dissolved minerals also raise the pH of the R/O water to less acidic. An ultra violet (U/V) sterilizer is used at the outlet.
None of the known prior art provides an in store self contained system that uses a R/O unit to anti-scale the water, then purify city water, calcify the water and inject potassium chloride to achieve a TDS ranging from 80-170 ppm, ideal for coffee and beverages.
Remineralization of the R/O water is accomplished by running the R/O water thru a calcite bed, then using an injection pump and TDS controller to specified set points using potassium chloride or other buffering ingredients. The ingredients in common re-hydration products such as Pedialite and sports drinks are of the chloride family (calcium chloride, potassium chloride. Magnesium chloride etc), also generically referred to as electrolytes. The present invention remineralizes and ph buffers the finished water. This gives the operator complete control of the constituents and the amounts used for remineralization. This also eliminates re-introducing undesirable constituents back into the finished water, such as nitrates, turbidity, off-taste etc. commonly introduced with a blendback system. The entire unit is preassembled, tested, disinfected and shipped on casters ready to be rolled in, connected to water, drain and power. No on-site assembly is required. The present invention provides this ideal water at the rate of several gallons per minute to a coffee shop and/or in store beverage bar.